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A mathematics teacher wanted to see the correlation between test scores and homework. The homework grade (x) and test grade (y) are given in the accompanying table. Write the linear regression equation that represents this set of data, rounding all coefficients to the nearest tenth. Using this equation, estimate the homework grade, to the nearest integer, for a student with a test grade of 42.

A mathematics teacher wanted to see the correlation between test scores and homework-example-1

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Answer: A student with a test grade of 42, the estimated homework grade is 42.

To find the linear regression equation, we need to calculate the slope (m) and y-intercept (b).

The slope represents the rate of change of the dependent variable (y) with respect to the independent variable (x), while the y-intercept represents the value of y when x is 0.

To calculate the slope (m), we use the formula: m = (Σ(xy) - (Σx)(Σy)/n) / (Σ(x^2) - ((Σx)^2)/n) where Σ represents the sum of the values, n is the number of data points, xy represents the product of x and y, and x^2 represents the square of x.

Let's calculate the values needed for the formula: Σx = 75 + 80 + 90 + 95 + 100 = 440 Σy = 82 + 85 + 92 + 88 + 95 = 442 Σxy = (75*82) + (80*85) + (90*92) + (95*88) + (100*95) = 41880 Σ(x^2) = (75^2) + (80^2) + (90^2) + (95^2) + (100^2) = 41650 n = 5

Substituting these values into the formula, we have: m = (41880 - (440*442)/5) / (41650 - (440^2)/5) m = (41880 - 97520/5) / (41650 - 96800/5) m = (41880 - 19504) / (41650 - 19360) m = 22376 / 22290 m ≈ 1

Now, let's calculate the y-intercept (b) using the formula: b = (Σy - m(Σx))/n

Substituting the values we have: b = (442 - 1(440))/5 b = (442 - 440)/5 b = 2/5 b ≈ 0.4

The linear regression equation is y = mx + b. Plugging in the values we calculated, the equation becomes: y = 1x + 0.4 y = x + 0.4

To estimate the homework grade for a student with a test grade of 42, we substitute the test grade (x) into the equation: y = 42 + 0.4 y ≈ 42.4 Rounding the estimated homework grade to the nearest integer, we get: Estimated homework grade ≈ 42 Therefore, for a student with a test grade of 42, the estimated homework grade is 42.

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